This invention relates to the field of animal husbandry, and particularly to swine production on a commercial scale. Experience has taught that in commercial swineries, where large animal populations are confined to small surface areas, proper sanitation is essential, not only for the health of the animals, but for that of the husbandmen as well. It has also become evident that the presence of workmen in an area inhabited by a population of swine is unwelcome both to the animals and to the workmen, and may be hazardous particularly in the presence of mother sows or boars of uncertain temperament.